*1:See also https://sumita-m.hatenadiary.com/entry/2020/01/04/162334 https://sumita-m.hatenadiary.com/entry/2020/02/07/005509 https://sumita-m.hatenadiary.com/entry/2020/02/09/125441 https://sumita-m.hatenadiary.com/entry/2020/02/11/082110 https://sumita-m.hatenadiary.com/entry/2020/02/26/094909 https://sumita-m.hatenadiary.com/entry/2020/03/02/082617